Percussive rotary rock drilling tool



June 28, 1960 R. w. BECK PERCUSSIVE ROTARY ROCK DRILLING TOOL 3 Sheets-Sheet 1 Filed Jan. 13, 1958 Robert W. Beck Inventor By IUQ7W Attorney FIG.-l

June 28, 1960 R. w. BECK 2,942,851

PERCUSSIVE ROTARY ROCK DRILLTNG TOOL Filed Jan. 13, 1958 3 Sheets-Sheet 2 t it FlG.-4

Robert W. Beck Inventor B/w W Attorney June 28, 1960 R. w. BECK 2,942,851

PERCUSSIVE ROTARY ROCK DRILLING TOOL Filed Jan. 13, 1958 3 Sheets-Sheet 3 Fig. 7

Robert W. Beck Inventor By W a. Q; Attorney United States Patent PERCUSSIVE ROTARY ROCK DRILLING TooL Robert Wm. Beck, Caracas, Venezuela, assignor, by mesue assignments, to Jersey Production Research Company Filed Jan. 13, 1958, Ser. No. 708,501

12 Claims. (Cl. 2554.4)

This invention relates to drilling apparatus for deep bores such as oil wells. It relates more particularly to drilling apparatus for such deep bores which must penetrate rock formations. It relates still more particularly to drilling apparatus in which a periodic percussive force is applied to the cutting elements or rock drill bit while these elements or this bit are being driven in rotary fashion; and it relates even still more particularly to drilling apparatus in which a hammer mechanism supplying periodic percussive forces to a rock drill bit is actuated by' fluid furnished to displace the drilling debris while the drill bit itself is rotated by other, independent means.

It is a well established fact that the addition of a percussive force to a drill bit during rotary drilling increases greatly the rate of drill penetration, particularly when ances of sliding and rotating parts, all undesirable because of being required to operate or exist while subject to submergence in abrasive drilling fluid.

It is the object of the present invention to provide a hammer means for applying a percussive force to a rotary rock drill bit, which means will be actuated by drilling fluid independently of the drill bit drive, and which will be of simpler and more reliable construction than any previously disclosed hammer means for the same pur- 'pose and similarly actuated. The invention and its object be more fully understood from the following description when it is read in conjunction with and with reference to the accompanying drawings in which:

7 Fig. 1 represents a vertical section through a rotary rock drilling tool showing the fluid-driven hammer mechanism of this invention.

Fig. 2 represents a transverse section through a rotary rock drilling tool taken along the line 22 of Fig. 1 showing'a sectorial fluid flow restrictor in closed position.

Fig. 3 represents a transverse section through a rotary rock drilling tool on the same plane as Fig. 2 showing a sectorial fluid flow restrictor in open position.

Fig. 4 represents a vertical section through the lower end of a rotary rock drilling tool showing an alternate form of the anvil and hammer head of Fig. 1.

Fig. 5 represents a vertical section through an intermediate length of a rotary rock drilling tool otherwise according to Fig. 1 showing shock absorber means.

Fig; 6 represents a transverse section through the apparatus shown in Fig. 5 taken along the line 66.

Fig. 7'represents a vertical section through the lower end of a rotary rock drilling tool showing an alternate 1 form of the fluid-driven hammer mechanism.

: Fig. 8 represents a transverse section through the I paratus' shown in Fig. 7 takenalong .thelinefi-S.

Referring now to Fig. 1, the percussive rotary rock drilling tool of this invention is shown attached to the bottom of a pipe string or drill collar 9 by a threaded joint. Any other suitable means of attachment may be used as well. In the tool itself 10 is a drill bit holder making connection at its upper end with the drill collar. This holder is generally tubular in form, and may be suitably parted and have appropriate joining means to allow installation of internal fittings. At its lower end holder 10 is threaded or otherwise suitably prepared to retain a replaceable drill bit assembly. This assembly comprises a base member 11 and cutting elements 12. Base member 11 has a centralcrown formation on its upper surface extending within drill bit holder 10, and around this crown has a plurality of fluid passageways 13. The crown of base member 11 is centrally drilled and tapped to receive a hardened replaceable anvil 14. The impact surface of this anvil is cut helically to provide at least one abrupt step as shown.

Within the holder 10 a turbine spindle assembly of which the cylindrical member 15 is the shaft is located concentrically and is supported by anvil 14. The outside diameter of shaft 15 is appreciably less than the inside diameter of holder 10 to provide an annular fluid passageway of substantial cross section area between the spindle'shaft and the holder. At its lower end, spindle shaft 15 is drilled and tapped to receive a hardened replaceable hammer head 16. On its impact surface this head is cut helically to provide at least one abrupt step, the same number as those on anvil 14 cut in such sense that the hammer head and the shaft to which it is aflixed will rise smoothly and then drop abruptly 'on the anvil as spindle shaft 15 is rotated.

The spindle assembly is guided vertically and concen trically in holder 10 by upper and lower bearings 17 and 18. These bearings are preferably rubber and cutless, and are fitted in retainer segments 19 and 20 which are located in grooves in the wall of holder 10. Segments 19 and 20 are extensively perforated vertically to provide fluid passageways in the bore of holder 10. At least one row of radially extending fluid guide vanes or blades 21 is set in drill bit holder 10. These are formed and spaced in such relation to an equal number of rows of radial blades 22 on shaft 15 that 21 and 22 comprise the fixed and moving blade elements of an axial flow hydraulic turbine. Spacing of vanes 21 and blades 22 must be such that the spindle assembly can rise and fall due to the inte'raction of hammer head 16 and anvil 14 without spindle blades striking holder vanes.

A flow restrictor sector 23 fitted in holder 10 extends inward horizontally. Likewise a restrictor sector 24 on spindle shaft 15 extends horizontally outward. Fig. 2 shows shaft 15 so turned in holder 10 that restrictor sector 24 is entirely out from under restrictor sector 23, and

downward flow of fluid through the annular space between'holder 10 and spindle shaft 15 is substantially blocked. Fig.3" shows the spindle assembly turned approximately from its position in Fig. 2 to bring the restrictor sectors substantially into line vertically and provide the greatest clear passage for flow of fluid past these restrictors. Referring back to Fig. 1, note that anvil 14 and restrictor sector 23 are stationary'with respectto holder 10, and hammer head 16 and restrictor sector 24 on spindle shaft 15 are so installed that the sectors reach their closed position as shown in Fig. 2 at approximately the same time the hammer head drops off the high point of the anvil.

. In the event that anvil 14 and hammer head 16 are each providedwith more than one step on their matching surfaces, the restrictor sectors should be redesigned accordingly. For example, if there be two steps on the hammerhead and anvil as shown in Figures 7 and} 9f "st-ring and. into the bore of drill bitholderwhile this holder and the bit assembly are being-rotated by means not shown. After passing through bearing retainer 19, the fluid enters the first row of guide vanes 21- which 'direct it against the first row of blades 22 on spindle shaft 151 imparting rotary motion 'to the spindle assembly relative to. the drill bit holder '16." The fluid then flows through any succeeding rows of vanes and blades giving :up further energy. to thespindle assembly. As'this as:- sembly. rotates it will alternately rise and fall as hammer head 16 rides up and then drops' abruptly on anvil 14. This abrupt drop will provide a' hammering action on the anvil, and a periodic percussive force will be transmittedto the cutting elements 12 with a frequency equal -t'r xthenumber of steps in anvil 14 times the rate of revolutionsof spindle: assembly withirespect to'bitholder {Fotal weight' of the hammer. be the' sum of the weightsofspindle shaft 15',hammer"head*16,. blades 22,

restrictor 24. After leaving the last row 15, the drilling fluid must flow through. openings between V sectorial-flow restrictors 23: which are continuouslybeing eovered and uncovered as restrictor sectors 24' on the 7 'spindIe shaft turn past them. When the openings past restrictors 23 are covered, fluidflow will be substantially blocked momentarily, and full 'fluid pumping pressure will be exerted on the upper-surfaces of. restrictors 24.

This-pressure will impart a'powerful downward thrust to the-Whole spindle assembly constituting the hammer just as highpoints onhammer head 16 ride off corresponding "points on anvil 14, and the hammer and the percussive force transmitted impact on the anvil to the cutting elements will be increased'accordingly. Once past the flow 'restrictors, the drilling fluid will continue down through bearing retainer 20, through drill bit base member 11, around cutting elements 12, and then up the annular 7 space between the pipe string and the wall of the hole being drilled to carry outits normal function of displacing} the drilling debris.

Fig. 4 shows adesign of" anvil and hammer head which supposes that all hammering force is to come from action offlow'restrictors 23 and 24. In this figure anvil 25 and hammer head 26 both have-flat instead of helical. and stepped impact surfaces. The hammer head is normally held out: of contact with the anvil: by a hardened ball 27 whichis backed by compression spring 28 set in a botthrust on the spindle assembly will be relieved to allow spring 28 to separate the hammerhead and anvil. Accordingly, the spindle assembly will rise and fall and deliver blows on anvil 25 without any cam action but simply through the working of the sectorial flow restrictors and spring 28.

With either of the hammer and anvil arrangements shown inFigs. l and 4, it is possible that undesirable shocks will be transmitted up the pipe string. This 'will depend on, among many things, the magnitude and frequency of the hammer impact and the dimensions of the pipe string. To localize hammer effects shock absorber means may be provided. A possible means is shown in Figures 5 and 6. In this figure 10a and 10b represent upper and lower drill bit holder sections. These sections are splined or otherwise flexibly connected longitudinally so that torque needed for the drill bit may be transmitted from upper section 10a .to lower section 10b. A suitably formed shock absorbing element 100 made ofv rubber or other appropriatematerial is interposed between the upper and lower drill bit holder sections. This element will dampen any shock waves passingup ward from drill bit holder lower section 1012. The shock ,so cif blades. on" spindleshaft tomed axial hole in the anvil. This ball must have a diameter less than that of the axial hole in the anvil. The spring must 'be' compressible to a height allowing full containment of the ball in the hole, and must be sulficiently' strong to sustain the weight of the entire spindle assembly with anything less' than nearly full fluid pump pressure on this assembly. At least one hole 29 is drilled radially through the anvil member to connect the annular an outside diameter appreciably.- less than'the. inside fr'uid passage with the spring recess in the anvil. This 7 hole allows fluid to flow freely in an out of the spring holein the anvil-with motion of the-ball and spring.

With the anvil and hammer headlarrangement of Fig. 4 substituted for that of Fig; l, the spindle assembly will 5 be driven. down by fluid pumping pressure 'to compress jgsirririg 28 and deliver a blow on anvil 25 as shaft 15 turns td-brihglthe flow restrictors into the closed relation to j Fig-2. As shaft 15 continues to turnand the flow restrictors assume the open relation of Fig. 3, static fluid absorber element maybe bonded to the upperand lower .drill bit holder sections, by appropriate means to prevent fluid leakage between'these sections.

"The advantages of the hammer mechanismswhich have been'disclosedare. numerous. Excepting therball 27 and spring 23 of Fig. 4"which move only slightly, the

sturdy'turbinespindle assembly is the sole moving part. "The cutless rubber bearings which guide this spindle are particularly well suited to operate submerged'in a somewhat. abrasive 'fluid. 'Fine clearances between spindle shaft and bearings are not needed, and" fluid passages in general are' of relatively generous size. A particular advantage is that the percussive force provided by this mechanism is not a'function only of the drop of a static hammer weight through a given distance. The'weight effect is augmented by hydraulic thrust accelerating the hammer as provided by operation of the sectorial flow restricto'rs. Indeed it has been shownthat periodic percussivev force on the drill bit may be providedby such operation alone.

What is claimed is: 7 r

1'. A percussive rotary rock drilling tool comprising; a tubular drill bit holder for attachment to the lower end .of a pipe string; a drill bit assembly removably secured to. the lower end of said holder and having a plurality of fluid passages therein to form'continuations of thebore of said holder; a hardened. anvil member with upper surface helically cut to provide at least one abrupt cam step. removably secured in the; center of; the upper surfall abruptly onto said anvil member in the. course of rotation relative thereto, whereby providing. percussive action through at least its own weight upon said anvil member, said spindle assembly comprising a shaft having diameter of said holderv whereby an annular passageway for fluid flow between said shaft and said holder is formed, a hardened hammer head member. with. lower surface cut similarly to. the upper surface of said anvil memberbut to the opposite hand removably secured to the lower end of said shaftiand at least one row ofprojections set circumferentially around said "shaft and extending outwardly therefrom, said projections being shaped appropriately for moving blades of a fluid powered axial flow turbine; and a number of rows ofprojections equal to. the number on said shaft set circumferentially around the inner wall. of said holder and extending inwardly therefrom, said projections being shaped appropriately for stationary; blades. ofza. fluid powered axial flow turbine, and said rows of projections in said holder being set' at such height and with such spaced relation therein to mesh with said rows of projections on said shaft as fixed and moving blade'elements of an axial flow turbine operableby drilling fluid flowing downwardly through said drill bit holder.

2. A percussive rotary rock drilling tool according to claim 1 in which said spindle assembly is freely guided vertically and concentrically Within said drill bit holder by upper and lower bearing'assemblies set circumferentially in longitudinally spaced relation in said holder and extending into and extensively perforated for fluid flow in the bore of said holder.

3. A percussive rotary rock drilling tool according to claim 2 in which said bearing assemblies comprise hearing retainer segments and cutless rubber bearing elements.

4. A percussive rotary rock drilling tool according to claim 1 in which said drill bit holder comprises upper and lower sections having a longitudinally flexible joint capable of transmitting torque needed for said drill bit from said upper section to said lower section, and shock absorbing means interposed between said upper and lower sections.

i 5.- A percussive rotary rock drilling tool comprising a tubular drill bit holder for attachment to the lower end of a pipe string; a drill bit assembly removably secured to the lower end of said holder and having a plurality of fluidpassageways therein to form continuations of thebore of said holder; a spindle assembly freely guided vertically and concentrically in said holder comprising a shaft having an outside diameter appreciably less than the inside diameter of saidholder whereby an annular passageway for fluid flow between said shaft and said holder is formed,- and at least one row of projections set circumferentiallyeround said shaft and extending out Wardly therefrom, said projections being shaped appropriately for moving bladesof a fluid powered axial flow turbine; a. numbervof rows of projections equal to the number on saidv shaft set .circumferentially around the inner ,w'allof said .holder. and extending inwardly therefrom; said projections. being shaped appropriately for stationary blades of a fluid powered axial flow turbine, and said rows of projections in said holder being set at such height and with such spaced relation therein to mesh with said rows of projections on said shaft as fixed and moving blade elements of an axial flow turbine operable by drilling fluid flowing downwardly through said drill bit holder; means for supporting said spindle assembly on said drill bit assembly whereby said spindle can be rotated and rise and fall with respect to said drill bit and deliver a hammer blow thereon; and fluid thrust means comprising a first flow restrictor sector of approximately 180 included angle aflixed to said spindle shaft and extending outwardly therefrom to a radius slightly less than the inner radius of said holder and a second flow restrictor sector of approximately 180 included angle aflixed to said drill bit holder and extending inwardly from the inner wall thereof to a radius slightly larger than that of said spindle shaft and having a closely spaced axial relation to said first flow restrictor sector whereby a sectorial fluid flow passage in the bore of said can be rotated and rise and fall with respect to said drill bit and deliver a hammer blow thereon comprises a hardened anvil member removably secured in the center of the upper surface of said drill bit assembly within the bore of said holder, said anvil member having its upper surface helically cut to provide an abrupt cam step; and a hardened hammer head member with lower surface cut with an abrupt step cut similarly to' the upper sin face'of said anvil member but to the opposite hand removably secured to the lower end of said spindle shaft, the orientation of said anvil member with respect to said drill bit holder and of said hammer head member with respect to said spindle shaft being such that the abrupt step on said hammer head will be aligned with the step on said anvil when said first flow restrictor sector aflixed to said'spindle shaft is so oriented with respect to said second flow restrictor sector aflixed to said holder to substantially close the bore of said drill bit holder.

7. A percussive rotary rock drilling tool according to claim 5 in which said means for supporting said spindle assembly on said drill bit assembly whereby said spindle can be rotated and rise and fall with respect to said drill bit and deliver a hammer blow thereon comprises a hardened anvil member removably secured in the center of the upper surface of said drill bit assembly within the bore'of said holder, said anvil member having a fiat upper surface and being provided with a bottomed axial hole opening through its upper surface and at least one radial hole from its outer side surface to said axial hole; a hardened hammer head member removably secured to the lower end of said spindle shaft, said hammer head having a flat lower surface; a compression spring seated and freely workable in said axial hole in 'said anvil; and a hardened ball surmounting said spring whereby it is pressed against thelower face of saidhammer, said ball havingia diameter less than thatof the axial hole in said anvil member; and said spring being compressible to such height torallow full containment ofsaid ball insaid axial hole, and being of'such. strength-to support said hammer head and spindle assembly out of contact with said anvil member in the absence of substantial fluid pressure on said first flow restrictor sector aflixed to said spindle in its, positionwith respect to said second flow restrictor sector affixed to saiddrill bit holder wherein the 'base of said holder is substantiallyclosed.

8. A percussive rotary rock drilling tool according'to claim 5 in'which said drill bit-holder comprises upper and lower sections having a longitudinally flexible joint capable of transmitting torque needed for rotation of said drill bit in normal drilling device from said upper to said lower section, and shock absorbing means interposed between said upper and lower sections.

9. A percussive rotary rock drilling tool comprising a tubular drill bit holder for attachment to the lower end of a pipe string; a drill bit assembly removably secured to the lower end of said holder and having a plurality of fluid passageways therein to form continuations of the bore of said holder; a spindle assembly freely guided vertically and concentrically in said holder comprising a shaft having an outside diameter appreciably less than the inside diameter of said holder whereby an annular passageway for fluid flow between said shaft and said holder is formed, and at least one row of projections set circumferentially around said shaft and extending outwardly therefrom, said projections being shaped appropriately for moving blades of a fluid powered axial flow turbine; a number of rows of projections equal to the number on said shaft set circumferentially around the inner wall of said holder and extending inwardly therefrom, said projections being shaped appropriately for stationary blades of a fluid powered axial flow turbine, and said rows of projections in said holder being set at such height and with such spaced relation therein to mesh with said rows of projections on said'shaft as fixed and moving blade elements of an axial flow turbine operable by drilling fluid flowing downwardly through said drill bit holder; means for supporting said spindle assembly on said drill bit assembly whereby said spindle can be rotated and rise and fall with respect to said drill bit and deliver a hammer blow thereon; and fluid thrust means comprising a first set of at least two coplanar fluid flow restrictor sectors of mutually equal individual included angles and having a 'totaliincludedangleiofjappr xim fi y 1180."; aflixed to said Spindle; shaft with evenangular; spacing. about; the circumference thereof and; extendingmt:

wardly therefrom to; a;radius, slightly less than; the inner radiusof; said holder anda. second; schof; coplanar fluid o restrictori sectors, the same inrnumher as the: r strictor'sectorsin said first se t,,van;dj halving'mutuallyrequal individual included angles and; a total, included angle of approximately 180, afiixedjtorsaid drill, bitholder with even: angular spacing about "the: inner wall thereof; and extending inwardly therefromgtoa, radius slightlylarger than-that oftsaid, spindleshafitandhavingaplosely spaced akial relation to said restrietorasectors oflsaid; first set whereby at: least two sectorial fluidgflovw passages; the

' bore of: said. bit; holder; alternately jopenable: and

closeable togetherv by rotary motionof;said-ispindle;with respectzto; s id holder reprovidedl j 170.: A p rcus ive. rotaryrock drilli g tqol: according tov'claim; 9 in Whichsaid'; meansionsupporting saidspindle assembly on-said drill bit; ssemb y ereby aid pindle can lie-rotated; andliseandsfall.withlespe trtosaid dr ll bit; and eliver a ammer: blow her cnd omp ises h rdened anvil; member removablv secured, 1 in: the: Q nter oithe upper surface ofisaidgdrill, bit.- assembly within the bore of said: holder, said;anvil;member'having itsrupper su rfacelcut helically. to' provideamumbenof: evenly. spaced abrupt cam steps'equal to the number: of flovwrestrietor sectors insaid second set thereof edited to:' said 'drill bit holder; and a hardenedhamm'erhead membenwitlis lower surface cut helically with abrupt stepssimilarly' tothe upper surface ofsaid anvil'me'mbj'er but toftheopposite hand removably secured'to lower end-mffsaids'pindle shaft, the orientation of'said anvil member with respect to saiddrill b'it holder andofjsaidihammer head. member with respect to said spindle shaftbeing rsuchi that an 7 radial hole from'itsouter'sidesurface tg saidtaxial hole;

ahardened hammerhead member removablyfsecureddo the lower end of said spindle, shaft, said? hammerhead having a flat lower surface; acompression spring seated andfreely workable insaidaxial hole in said anvil; and a. hardened ball: surmounting; said spring whereby it, is pressed against the lower face of said hammer head, said ball having a diameter-less:than that of the axial hole. in

' said anvil member, and said" spring being compressible to such height to allow full containment ofnsaidballrin said axialhole, andbeing of snchstrength.to;-support,said hammerhead and; spindle assembly out of contact with said anvil member in the absence, oftsubstantial fluid-pres,- sure on said first set of flow restrictor sectors afiixed to said spindle in. a position with respect tQSfild-SQCOBdQSCt ofj flow restrictor sector's affixed' to-said:drills bitholder wherein the bore of saidholder issubstantially closed.

' i l2. A percussive, rotary rock; drilling. tool according to abrupt step on said hammer head be aligned'witha step on said anvil whenever saidr first, set of, flowi restrictor sectors affixed, tosaidspindle shaft. is .so, oriented with respect to said second set offlow.restrictor sectors afi'ixedtotsaid holder tosubstantially; close; thebore, of said drillbitholder. 3

claim. 9 in which, said bit: holder, comprises upper and lower sections having a-longitudinally flexible joint capable of transmitting torque. needed. for rotation of said drillzbit inrnormal drillingservice fromsaid: upper .to said lower section, and, shock abso rhing gmeansinterposed between said upper andrlower-sections.v 7

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